Arizona's 1st congressional district is a congressional district located in the U.S. state of Arizona, covering northeastern Maricopa County. Before 2023, geographically, it was the eleventh-largest congressional district in the country and included much of the state outside the Phoenix and Tucson metropolitan areas. From 2013 through 2022, it also included the Navajo Nation, the Hopi reservation, and the Gila River Indian Community, with 25% of the population being Native American. At that time, the district had more Native Americans than any other congressional district in the United States. In the 2022 elections, David Schweikert was elected in the redefined district. It was one of 18 districts that would have voted for Joe Biden in the 2020 presidential election had they existed in their current configuration while being won or held by a Republican in 2022.

Maricopa County is in the south-central part of the U.S. state of Arizona. As of the 2020 census the population was 4,420,568, or about 62% of the state's total, making it the fourth-most populous county in the United States and the most populous county in Arizona, and making Arizona one of the nation's most centralized states. The county seat is Phoenix, the state capital and fifth-most populous city in the United States.